Green tomato ketchup

This is a traditional recipe from Quebec, very useful if you grow your own tomatoes and are left with a glut of unripened ones when it gets too cold to keep them outside. This sweet and tart ketchup can smarten up simple things like cheese and crackers or sandwiches, but also does a great accompaniment for steak. This recipe should fill up about 12 Mason jars.

8 cups (1,6 kg) green tomatoes

3 cups (450 g) onions

2 tablespoons salt

2 cups vinegar (white or cider vinegar, to taste)

1 cup sugar

2 tablespoons mustard seeds

1/2 teaspoon celery seeds

Peel the tomatoes (as they will be hard this is easily done with a potato peeler) and cut into 1/2 inch dice. Place all into a large bowl with plenty of salt and leave to rest for an hour. Slice your onions into thin strips.

In a large saucepan, pour the vinegar, sugar, celery and mustard seeds and bring to boil.

Add the tomatoes and onions and stir to coat everything in the vinegar/sugar mix. Cover and simmer until the vegetables are soft (about 2 hours), stirring from time to time.